They tend to bend the rules also in terms of the formal qualities. Mannerist art takes many of its schemas from Michelangelo but they tend to exaggerate the qualities found in his art. The figures always seem to be perched on the edge of action. Often they are portrayed in the moment just before they rise up from a chair. They are nether seated nor are they actually moving. Often the figures' anatomies are weird, twisting and distorted. Heads are too small, figures seem to float in ambiguous space and the color and value structure are often over emphasized or exaggerated unnaturally.
Form: Correggio's style of painting is almost a shopping list of what a Mannerist painting should look like. Correggio paints the fantastic in an illusionistic and believable manner. The cloud, which is Zeus in disguise, is rendered in a believable manner. The figure of Io's anatomy is distorted. The head is a bit too small and the torso is elongated but on first glance it seems believable. The pose is somewhat improbable but again it looks real.
The space he creates is also a twist on earlier depictions of space. Here Correggio foregoes the illusion of deep space and pushes the whole scene up against the picture plane and the space around it is strange. The viewer after a closer look at the painting is forced to ask themselves, "where is this taking place?"
Iconography: Correggio even takes the idea of classicism and the depiction of classical mythology and puts a spin on it.
Io was a priestess of the Roman goddess Juno. Juno was the jealous wife of Jupiter, the king of the gods. Jupiter was indeed very unfaithful. When Jupiter fell in love with Io, he transformed himself into the shape of a dark cloud to hide himself from his jealous wife.
However, noticed the small cloud and suspected that the cloud was one of Jupiter's tricks. Thus, she approached to check the true nature of the cloud. As soon as Juno arrived, Jupiter immediately transformed Io into a white cow to avoid his wife's wrath. But Juno guessed the intrigue and asked if Jupiter wanted the cow as a gift. Jupiter could not refuse such a little gift without giving himself away.
Thus, Juno tied the poor cow and sent her faithful servant Argus to watch over Io. Argus had a hundred eyes and only a few were ever closed at any time. To free Io, Jupiter sent his son Mercury to sing and tell boring stories to make Argus sleep with all his eyes. Mercury told so many stories that finally Argus close all his hundred eyes. Only then did Mercury kill Argus and untie Io, who ran home free.
Yet when Juno discovered what had occurred, she was so furious that she sent a vicious gadfly to sting the cow forever. Moreover, to honor the memory of her faithful servant, Juno put the hundred eyes of Argus on the tail of her favorite bird, the peacock. The hundred eyes could not see any more but beautifully decorate the tail of the peacock.
Meanwhile, Io, who was still prisoner into the shape of a cow, could not get rid of the malicious gadfly. Finally, after Jupiter vowed to no longer pursue his beloved Io, Juno released Io from her inhuman prison, and Io settled in Egypt, becoming the first queen of Egypt.
This tale is not a moralizing one but rather an excuse to show a semi erotic scene under the disguise, much like Titian's Venus of Urbino, of a classical or humanistic theme.
Context: Correggio and other Mannerist artists of his day were catering to the new, somewhat controversial tastes of his clients.
"At the height of his career while working for the Duke of Mantua, Frederigo Gonzaga (1530-33), Correggio painted a group of works for presentation to Emperor Charles V representing the loves of Jupiter ("Leda", "Antiope", "Ganymede", and "Io")."